Air cushion vehicle cell having rigid base

ABSTRACT

A rigid base is provided for each of a series of air cushion seals of the type customarily found on the periphery of so-called Hovercraft or &#39;&#39;&#39;&#39;surface effect&#39;&#39;&#39;&#39; ships; and each of the bases may be controlled either externally or in response to sea fluctuation conditions.

United States Patent 'Eggington 1 Oct. 21, 1975 AIR CUSHION VEHICLE CELL HAVING 3,272,272 9/1966 Hall et al. 180/122 x RIGID BASE 3,363,718 1/l968 Hammett 180/128 3,473,503 10/1969 Gunther l80/l26 X Inventor: Wllfl'ed James Eggmgto 3,504,755 4/1970 Bliss et al l80/l2l x Claremont, Calif. 3,631,938 1/1972 Eggington 180/124 3,700,065 l0/l972 Eggington l80/l2l X [73] Asslgnee' a sysiems Inc-1 Beverly 3,752,253 8/1973 Hopkins et al l80/l27 22 F1 d: A 30 1973 1 pr Primary Exarr'zin'f-Kenneth H. Betts PP N03 355,510 Attorney, Agent, or FirmAlan C. Rose; Thomas A. [44] Published under the Trial Voluntary Protest Turner 7 Program on January 28, 1975 as document no.

57 ABSTRACT [521 US. Cl. 180/121; 180/123; 180/124; 1

2 180/126 A rigid base is provided for each of a series of air [51] Ill". Cl. B60, 1/04 cushion Seals of the yp customarily found on the p [58] Fleld of Search 180/124, 121, 122, 1.27, ip y of So ca"ed Hovercraft or Surface f 123 ships; and each of the bases may be controlled either externally or in response to sea fluctuation conditions. [56 References CIted UNITED STATES PATENTS 5 Claims, 4 Drawing Figures 3,267,882 8/1966 Rapson et al. [80/124 X US. Patent Oct. 21, 1975 Sheet 1 of2 3,913,704

US. Patent Oct. 21, 1975 Sheet 2 of2 3,913,704

AIR CUSHION VEHICLE CELL HAVING RIGID It has been known before to use'air cushions to suspend a ship during transport above water, or perhaps land or marshy land. Such a vessel is conventionally known as a Hovercraft, or in the vernacular sometimes as a surface effect ship," or more simply as an SES. Conventionally, these surface effect ships are suspended on the air cushion, with the air cushion surrounded on the periphery of the surface effectship by a skirt. Such skirts have been shown to be'cellularin structure, as for example in U.S.Pat. No. 3,631,938 to Eggington. These skirts form the buffer on which waves, tall grass, and other seaand marsh-imposed conditions react. Many problems have arisen when the wave or other shock-like condition strikes the skirt, and the skirt fails to adjust in immediate response to the shock-like condition. The failure of the skirt to adequately respond to the shock condition, it is felt, has been the causeof such hovercraft plowing-under and capsizing, as several have done in recent times. Thus, it is important and urgently needed in the art to provide a celllike Hovercraft skirt which will immediately, automatically and adequately respond to shock conditions which the sea or inarshland will present to the vessel.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 Illustrates a perspective view of the invention in its normal environment;

FIG. 2 Illustrates a fragmentary side elevational view of the preferred embodiment of the invention;

FIG. 3 Illustrates a plan fragmentary view of the invention in the preferred embodiment; and

FIG. 4 Illustrates an alternative embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT To achieve the desired end, a new construction of a skirt 12 has been discovered for placement about the lower periphery of the conventional Hovercraft vessel 10, reference being had to FIG. 1. The air cushion 18 is surrounded on the periphery of the vessel by skirt 12. In the present, preferred embodiment, it is contemplated that this skirt 12 will be constructed, at least on its forward bow and stern peripheral sections, with cells to be described in more detail below. Such new construction is explained and understood more clearly when the view along line 22 in FIG. 1, shown in detail in FIG. 2, is understood.

In FIG. 2, an air-seal cell 20 is shown depending below the outside edge or periphery of the raft 16 of the vessel 10. The cell 20 consists of flexible walls 22 which enclose the cell 20. The cells 20 are thus freely capable of vertical compression and extension. The walls 22 are disposed in airtight relationship with the underside of the raft 16. The lower end of the cell is comprised of a rigid seal base 30 which is in airtight coupling with the flexible walls 22.

In the preferred embodiment of the forward cells 24, the forward end of wall 22 extends to a distance shorter than the rearward end of wall 22 so that when the forward cells 24"are extended, the forward edge of the rigid seal base 30 maintains a higher altitude relative to the water level 28 than does the rear edge of the rigid base 30. An orifice 32 placed in the rigid base 30 so that air inside the cell 20 can freely pass to the underside of the rigid base 30. In the preferred embodiment as shown in FIG. 2, the orifice 32 is constructed so that the orifice lip of the rear section of the rigid base 30 overlaps the orifice lip of the forward section of the rigid base 30, for reasons to be described in more detail below. I

While in FIGS. land 3 the side skirts 12 of the vessel 10 are shown as being solid, it is understood that the cellular construction of the bow peripheral portions can be substitutedtherefor. For any such side cells, and for the stern cells 26, .the same rigid base as described above and in FIG. 2 could be provided, i.e., having a higher forward; edgerelative to the rearward edge. Of course, there need not bev as much of a difference between the forward and rearward altitudes as in the bow 'ce'lls. Design considerations should dictate that there be slightly higher altitude on the forward edge of rigid base 30 than on the following edge. A cell system having direct pneumatic contact between adjacent cells is preferred. The individual cells 20 may be pneumatically separate from each other, and individually supplied with air under pressure. Air to the cells 20 would be supplied through conduits 52 from air coinpressor 50, as shown in FIG. 3. Thecells would then be provided with inter-pneumatic contact for air pressure equalization among the cells, if that is desired. In any event, the cells 20 are in airtight relationship to each other, such that no air from the central air cushion 18 will escape therebetween. In the most preferred manner, air cells 20 having adjacent cell direct pneumatic contact could be arranged to receive, additionally, air under pressure from conduits 52 individually at the same time.

Optional, but preferred is the provision of a skirt 34 which depends downwardly from the forward edge of the rigid base 30. This skirt 34 can be flexible, but should be allowed to pivot rearwardly from its connection with the rigid seal base 30. A connection 35, such as a wire perforated plane, or the like may be provided to restrain the skirt 34 from pivoting forwardly.

A control tie 36 extends from the rigid seal base 30 to power control means within the vessel 10, not shown. Thus, the operator or captain of the surface effect ship can either manually, or by remote automatic powered means, control the vertical movement of the control tie 36, and consequently the vertical disposition of rigid seal base 30. The control tie 36 is optional to the performance and practice of this invention, as will be shown.

An optional alternative to the configuration of rigid seal base 30 is shown in FIG. 4. As shown, the base sections 31 and 33 can be progressively canted so as to ensure good planing characteristics in all anticipated water surface conditions.

in operation, the new skirt cell operates in thefollowing manner. Compressed air from an air source 50 is conveyed throughair ducts 52 into a cell 20, as

shown by the arrows 42. The air pressure acts against the inside of walls 22 and against the upper side of base so to extend thewalls 22 and the base 30 to their optimum extension, asshown by arrows 44. Some air escapes from the cell 20 to the underside of base 30 through the orifice 32. This escaping air is generally held within the area between the water level 28 and the lower side of the forward portion of base 30 by the skirt 34. The water 28 provides an upward force against base 30 at the bases rearward end, as indicated by arrow 46.

The air withincell 20, indicated generally by arrows 42, 44, acts against the air pressure from the air cushion 18 on the rearward flexible wall 22, against the water pressure on rigid base 30, indicated by arrow 46, and, against the normal, inertial atmospheric air resistance in the forward flexible wall 22 by the forward movement of the vessel =10, indicated generally by arrows 48.

Normally, the rigid base 30 skims or planes across the water surface 28 when the vessel 10 is in transport. Air pressure 42, 44 maintains the base 30 extended from the vessel 10 and in contact at its rearward end with the water surface 28. When a wave or other shock-like pressure comesagainst the forward edge of the vessel, skirt 34 retreats inwardly to accommodate the wave. Air pressure normally found between the water level 28 and the forward edge of the base 30 increases so as to form a natural, upward. pressure indicated by arrow 60 If the wave is largeenough, the pressure 60 will exert such an upward force as to overcome the downward force of pressures 42, 44 and the rigid base 30 will re- 4 t l lnsuch a manner, it can be seen that an automatically responsive, rigid seal, improved cellular skirt isprovided for conventional Hovercraft or surface effect ships,.making the air cushion skirt more controllable and more safe.

I claim:

I. An air cushion vessel having a periphery about a.

hull and supported upon a large central air cushion during transport, comprising: a. at least one air cushion cell disposed depending from at least a bow section of said periphery forming a bow seal for said larger, central air cushion b. each said cell including a flexible wall and capable. 4 of vertical compression, and fixed at its upper end to said periphery of said vessel, said cell being; pneumatically connected to a source of air pres sure;

c. each said cellfurther including a rigid base oriv ented at a planing angle relative to the desired di rection of movement of the vehicle, said rigid base having an orifice therein for allowing air to escape to below said base and d. at least a portion of said rigid base disposed in substantial contact with a surface over which said vessel transports. 2. The vessel as claimed in claim 1, said cell further comprising a rigid, selectively controllable tie rod fixed at one end of said rigid base, said tie rod disposed at a.

second end to selective control means.

3. The vessel as claimed in claim 1, wherein said air under pressure is selectively controllable.

4. The vessel as claimed in claim 1 further including atleast a second said air cushion cell disposed depending from at least a stern section of said periphery forming'a stern seal for said larger, centralair cushion.

5. The vessel as claimed inclaim 4 wherein said bow seal and said stern seal each comprise a plurality of smaller air cushion seals disposed in adjacent, airtight relationship. i

* k I i 

1. An air cushion vessel having a periphery about a hull and supported upon a large central air cushion during transport, comprising: a. at least one air cushion cell disposed depending from at least a bow section of said periphery forming a bow seal for said larger, central air cushion; b. each said cell including a flexible wall and capable of vertical compression, and fixed at its upper end to said periphery of said vessel, said cell being pneumatically connected to a source of air pressure; c. each said cell further including a rigid base oriented at a planing angle relative to the desired direction of movement of the vehicle, said rigid base having an orifice therein for allowing air to escape to below said base; and d. at least a portion of said rigid base disposed in substantial contact with a surface over which said vessel transports.
 2. The vessel as claimed in claim 1, said cell further comprising a rigid, selectively controllable tie rod fixed at one end of said rigid base, said tie rod disposed at a second end to selective control means.
 3. The vessel as claimed in claim 1, wherein said air under pressure is selectively controllable.
 4. The vessel as claimed in claim 1 further including at least a second said air cushion cell disposed depending from at least a stern section of said periphery forming a stern seal for said larger, central air cushion.
 5. The vessel as claimed in claim 4 wherein said bow seal and said stern seal each comprise a plurality of smaller air cushion seals disposed in adjacent, airtight relationship. 